The only way to do that is to manipulate the independent variable and observe any changes in the dependent variable. Because it would be unethical to expose a randomized group of people to high levels of vehicle exhaust,[1] a study comparing two populations with differential exposure to vehicle exhaust would rely on a natural experiment, or a situation in which this already occurs due to factors unrelated to the researchers. The company approaches several gyms near its headquarters. SPICE (Setting, Perspective, Intervention/phenomenon of Interest, Comparison, Evaluation) Appropriate for : evaluating the outcomes of a service, project, or intervention Expected to influence the dependent variable, Doesn't change as a result of the experiment, Can be manipulated by researchers in order to study the dependent variable, Expected to be affected by the independent variable, Expected to change as a result of the experiment, Not manipulated by researchers; its changes occur as a result of the independent variable. This helps you to have confidence that your dependent variable results come solely from the independent variable manipulation. Independent Variable vs Dependent Variable - Systematic Reviews in the We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. This includes rankings (e.g. These concepts should not be confused with predictor and outcome variables. One is called the dependent variable, and the other is the independent variable. An example of a dependent variable is how tall you are at different ages. Verywell Mind content is rigorously reviewed by a team of qualified and experienced fact checkers. Here are several examples of independent and dependent variables in experiments: In a study to determine whether how long a student sleeps affects test scores, the independent variable is the length of time spent sleeping while the dependent variable is the test score. Each athlete will run on a treadmill for one hour while their heart rate is tracked. A company that specializes in essential oils wants to examine the effects of lavender on sleep quality. The dependent variable is the variable that is being measured or tested in an experiment. A group of health scientists decides to conduct a study to determine if taking vitamins improves health. A sports medicine researcher has been hired by Gatorade to test the effects of its sports drink on athletic performance. How should we measure stress? Fact checkers review articles for factual accuracy, relevance, and timeliness. Changes in . MeSH You will probably also have variables that you hold constant (control variables) in order to focus on your experimental treatment. Researchers want to determine if a new type of treatment will lead to a reduction in anxiety for patients living with social phobia. Nominal, Categorical, Dichotomous, Binary. It represents the cause or reason for an outcome. Data is generally divided into two categories: A variable that contains quantitative data is a quantitative variable; a variable that contains categorical data is a categorical variable. Dv examples | Math Index A well-known fast-food corporation wants to know if the color of the interior of their restaurants will affect how fast people eat. In an experiment, one group of students attends an after-school tutoring session twice a week while another group of students does not receive this additional assistance. Journal of Health Care Chaplaincy, 20(4), 161170. The independent variable was the airbag and the dependent variable was the amount of skull damage. These variables are created when you analyze data, not when you measure it. Are researchers trying to identify how the variable influences another variable? The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression. Groups that are ranked in a specific order. We could measure blood pressure, or the amount of the stress hormone cortisol in their blood, or by using a paper and pencil measure such as a questionnaire that asks them how much stress they feel. The independent variable is hair color, and the dependent variable is pupil dilation. Accessibility Instead, you can create a research design where you compare the outcomes of groups of participants with characteristics. The dependent variable would be the amount of liquid absorbed by the paper towel. The patients are randomly assigned to one of three groups: one group receives no chemotherapy, one group receives a low dose of chemotherapy, and one group receives a high dose of chemotherapy. The number of popped kernels is the dependent variable. A confounding variable is related to both the supposed cause and the supposed effect of the study. A change in the independent variable directly causes a change in the dependent . Example one: How long you use your phone before bed affects your quality of sleep. A correlation reflects the strength and/or direction of the relationship between two (or more) variables. These terms are especially used in statistics, where you estimate the extent to which an independent variable change can explain or predict changes in the dependent variable. Published on Saul Mcleod, Ph.D., is a qualified psychology teacher with over 18 years experience of working in further and higher education. Information biasrefers to a systematic error due to inaccurate measurement or classification of disease, exposure, or other variables.[3] Recall bias, a type of information bias, occurs when study participants do not remember the information they report accurately or completely. Measures of central tendency in chaplaincy, health care, and related research. Applying causal mediation analysis to personality disorder research. Here are some examples of research questions and corresponding independent and dependent variables. For example, in an experiment about the effect of nutrients on crop growth: The independent variable is the amount of nutrients added to the crop field. In this animal study, the independent variable would be car exhaust and the dependent variable would be amount of time to run a maze. Then the crash experts rammed each car into a crash wall at the same speed. An operational definition describes exactly what the independent variable is and how it is measured. Each participant sits in a booth and takes a bite of one version of the crust. But there are many other ways of describing variables that help with interpreting your results. government site. Salt tolerance in plants cannot be measured directly, but can be inferred from measurements of plant health in our salt-addition experiment. Each of these types of variables can be broken down into further types. Each shopper is given a box of the same food and drink items and sent to one of the rooms. For example, in an experiment about the effect of nutrients on crop growth: Defining your variables, and deciding how you will manipulate and measure them, is an important part of experimental design. A hospital is investigating the effectiveness of a new type of chemotherapy on cancer. Here the independent variable is the dose and the dependent variable is the frequency/intensity of symptoms . 8600 Rockville Pike The independent variable is the color of the room, and the dependent variable is the amount of time spent in the room eating. 7 Examples of a Hypothesis To Inform Your Research Lack of sleep significantly affects learning in 10-year-old boys. At the same time, software on the computer that utilizes the computers camera is measuring each males pupil dilation. ThoughtCo, Aug. 27, 2020, thoughtco.com/independent-and-dependent-variable-examples-606828. What are independent and dependent variables? If you are having a hard time identifying which variable is the independent variable and which is the dependent variable, remember the dependent variable is the one affected by a change in the independent variable. An independent variable is the variable you manipulate or vary in an experimental study to explore its effects. Is the variable one that is being manipulated by the experimenters? For the following hypotheses, name the IV and the DV and operationalize both variables. At the end of three months, the muscle mass of all participants is measured. Half are given Gatorade, and the other half are given water, but no one knows what they are given because both liquids have been colored. Each version contains a different blend of specially developed chemicals. Revised on December 5, 2022. Then, you select an appropriate statistical test to test your hypothesis. For example, if you're studying whether a change in temperature affects productivity, the independent variable would be the room temperature, and the dependent . How someones age impacts their sleep quality, How different teaching methods impact learning outcomes. . ____________________________________________________________. Your email address will not be published. You want to know which brand of microwave popcorn pops the best. Any measurement of plant health and growth: in this case, plant height and wilting. There are two main types of independent variables. Examples of Independent Variables in Research Studies A Dependent variable is what happens as a result of the independent variable. The first is that the researchers manipulate, or systematically vary, the level of the independent variable. Design approaches to experimental mediation. Linear Regression in Medical Research : Anesthesia & Analgesia - LWW Seekprofessional input on your specific circumstances. Independent and Dependent Variable Examples The presence/absence of the chemical is the independent variable. The action you just performed triggered the security solution. Next, they test the strength of each bridge by placing progressively more weight on its center until the bridge collapses. Independent and Dependent Variables | Definitions & Examples | Simply Statistical models will estimate effect sizes for the independent variables. It then proceeds to describe and discuss synonyms for the terms independent variable and dependent variable, including treatment, intervention, predictor, and risk factor, and synonyms for. It also makes it easier for other researchers to replicate a study and check for reliability. There can be all different types of independent variables. confounds; dependent variable; independent variable; levels of measurement; mediation; moderation; risk factors. A researcher wants to determine if the color of an office has any effect on worker productivity. In analytical health research there are generally two types of variables. The health of the plants (height, amount and size of flowers and fruit, color) is the dependent variable. Amanda Tust is a fact-checker, researcher, and writer with a Master of Science in Journalism from Northwestern University's Medill School of Journalism. Determining cause and effect is one of the most important parts of scientific research. A lot of those studies used an experimental design that involved males of various ages randomly assigned to play a graphic or non-graphic video game. Before rolling out a new type of crust, the company decides to conduct some research on consumer preferences. An independent variable is the variable you manipulate, control, or vary in an experimental study to explore its effects. *Note that sometimes a variable can work as more than one type! A large food company is considering entering the health and nutrition sector. 5.1 Experiment Basics - Research Methods in Psychology You have three groups: men, women and other. A confounding variable in the example of car exhaust and asthma would be differential exposure to other factors that increase respiratory issues, like cigarette smoke or particulates from factories. Independent variables are the variables that the experimenter changes to test their dependent variable. In other cases, researchers might find that changes in the independent variables have no effect on the variables that are being measured. Of course, there are a lot of issues to consider when conducting an experiment, but these are the basic principles. J Res Nurs. National Library of Medicine. In a study to determine whether how long a student sleeps affects test scores, the independent variable is the length of time spent sleeping while the dependent variable is the test score. (2010). Are you ready to take control of your mental health and relationship well-being? variable, or in the form (x2 + y2 ) dx dy 2xy = 0, where x is the dependent variable and y is the independent variable. You could also choose to look at the effect of exercise levels as well as diet, or even the additional effect of the two combined. It further explains that even though intervening, mediating, and moderating variables explicitly alter the relationship between independent variables and dependent variables, they help to explain the causal relationship between them. Dependent and Independent Variables - United States National Library of A variable is called dependent if a derivative of that variable occurs. The presence/absence of the chemical is the independent variable. This can happen when another variable is closely related to a variable you are interested in, but you havent controlled it in your experiment. Sometimes you may hear this variable called the "controlled variable" because it is the one that is changed. . You want to know which brand of fertilizer is best for your plants. Your dependent variable is math test scores. 3. Glossary - United States National Library of Medicine Once you have defined your independent and dependent variables and determined whether they are categorical or quantitative, you will be able to choose the correct statistical test. The dependent variable is the volume of liquid absorbed by the paper towel. Verywell Mind's content is for informational and educational purposes only. The review process on Helpful Professor involves having a PhD level expert fact check, edit, and contribute to articles. Subject variables are characteristics that vary across participants, and they cant be manipulated by researchers. The independent variable is Mozart, and the dependent variable is exam scores. Age is the independent variable. Would you like email updates of new search results? The independent variable and dependent variable are used in a very specific type of scientific study called the experiment. Although there are many types of bias, two common types are selection bias and information bias. Scientists want to know what causes changes in the dependent variable. Below is an example of using independent and dependent variables in an ecological study: A government agency handles environmental care in a city. ___________________________________________________________. You measure the math skills of all participants using a standardized test and check whether they differ based on room temperature. The independent variable is the variable the experimenter manipulates or changes and is assumed to directly affect the dependent variable. A randomized, controlled trial of meditation for work stress, anxiety and depressed mood in full-time workers. After a certain period of time, perhaps several months, the effects on cognitive performance could be measured. Here are the definitions for independent and dependent variables, examples of each variable, and the explanation for how to graph them. The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression. Independent and Dependent Variables: Differences & Examples Educators, social scientists, and parents were shocked at how graphic games were becoming.